| 摘要 |
<PICT:0903021/III/1> Silicon is produced at the heated tip of a mono- or poly-crystalline seed by directing a stream of silane and a surrounding stream of hydrogen on to the molten tip. The hydrogen is maintained at a temperature below that of decomposition of silane so as to prevent substantially the gas phase decomposition of the silane. The silane is at a molecular concentration substantially less than "normal". As shown in Figs. 1 and 2, silane is admitted through four tubes 17 and hydrogen through twelve surrounding tubes 18 in an outer tube 13 and the silane is decomposed at the upper surface of a seed 12 inductively heated by means of a primary coil 7, a secondary coil 8, and a work coil 10. The reaction product gas is withdrawn through a circular slot 15 around the inner periphery of an annular tube 15a connected to a tube 14 and a vacuum pump (not shown), the slot being kept free of silicon dust by means of a rotary wiper 16. The seed holder 11 is rotated and lowered as absorption of silicon proceeds to produce an elongated monocrystalline rod. The reaction vessel comprises glass cylinders 1 and 2, separated by the induction heating means, metal end plate 3, carrying tube 13 and metal end plate 4 carrying seed holder 11 and gas withdrawal tube 14. Specifications 745,698 and 826,575 are referred to. |
